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Wiring to "Code" Specs

 * Original msg to: Ramdrive-at-easilink-dot-com
 * Carbons sent to: usa-tesla-at-usa-dot-net

Quoting Jim Leonard <ramdrive-at-EASILINK.COM>:

 > Just curious Richard, What is your main service? 200 AMP or    
 > 100 AMP? Do you have electric heat? Most homes without         
 > electric heat are served with 100 amp service, ie 100 amp main 
 > breaker and 100 amps total current available from the good ol  
 > power company. To upgrade to 200 amp service, a new meter main 
 > is required, one rated for 200 amp service.

Hey, not to worry. I had the house mained for 200 amp service,
which is 100 amps heavier than the contractor recommended. The
house is all gas. There is no need to upgrade the mains or meter.

> Another point, in most states, a sub-panel must have the 
> neutral and ground busses seperated, I never quite understood 
> why, but that's the code.

The code requires two distinct ground paths, a neutral wire and a
ground. In this area metal conduit is approved for the ground.
Both busses are separate, but are tied together at the main
breaker box.

> I assume you used #4 copper, this is entirely suficient for 100
> amp service, however if you use aluminum, # 2 is required for 
> the two hot legs and number 4 for the neutral.

I specified that I purchased #4 AWG copper conductor.

> Just my two cents worth. I agree with you 100% as to
> doing the job first class in the beginning. I surely does save
> mega problems down the road. Providing good protection with 
> breakers/fuses is not a luxury.... it is a nessesity, 
> especially when dealing with the currents involved with big 
> coils.

Agreed.

> When the fields colapses on a transformer, a counter EMF spike
> can be generated. This spike can be hundreds of volts higher 
> than the input voltage and can be felt back down the line. 
> Installation of some heavy duty 150 volt metel oxide varistors
> between each hot leg and ground can protect the other devices
> in your home from those kicks. This is the same idea as the 
> spike protected outlet strips available to protect computers 
> and other sensitive electronics, but on a much larger and 
> higher current scale. 

This is probably overkill. The typical control circuit on a big
coil will employ several hundred pounds of copper and iron for
ballasting and voltage control in the form of inductive/resitive
current limiting and heavy variacs. This is sufficient in most
cases in preventing back EMFs from pushing into the mains. Also,
proper placement of the main system spark gap (across the line)
will keep the transformer core constantly energized. There will
still be some surging depending on the type of rotary gap
employed (synchronous or asynchronous). Running asynchronous
variable speed gaps as most of us do, and placing a few ohms of
resistance in parallel with the inductive ballast, will have the
line looking very smooth.

> You have proven time and time again to be extremely knolegeable
> not only in coiling, but also in practical electrical design. 

Why thank you very much for the complement. You sir made my day!

Richard Quick


... If all else fails... Throw another megavolt across it!
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